Geochemical, thermal and petrofabric analyses of Antarctic ice wedges: environmental influences
From 1998 to 2006, during four summer field seasons, ice wedges were found in 45 sites at depths ranging from 10 to 74 cm beneath the ground surface. The tops of the ice wedges ranged from 5 to 155 cm wide, and their heights varied from 20 to over 150 cm in length. A co-isotopic study was performed...
Main Authors: | , , , |
---|---|
Other Authors: | , , , , |
Format: | Conference Object |
Language: | English |
Published: |
Australian and New Zealand Geomorphology Group
2009
|
Subjects: | |
Online Access: | http://hdl.handle.net/11573/213993 |
id |
ftunivromairis:oai:iris.uniroma1.it:11573/213993 |
---|---|
record_format |
openpolar |
spelling |
ftunivromairis:oai:iris.uniroma1.it:11573/213993 2024-02-11T09:58:49+01:00 Geochemical, thermal and petrofabric analyses of Antarctic ice wedges: environmental influences RAFFI, Rossana B. STENNI L. GENONI O. FLORA Australian and New Zealand Geomorphology Group Raffi, Rossana B., Stenni L., Genoni O., Flora 2009 ELETTRONICO http://hdl.handle.net/11573/213993 eng eng Australian and New Zealand Geomorphology Group country:AUS place:MELBOURNE info:eu-repo/semantics/altIdentifier/isbn/9781877040740 ispartofbook:Conference Abstracts 7th International Conference on Geomorphology (ANZIAG). Ancient Landscape-Modern Perspectives firstpage:1 lastpage:1 numberofpages:1 http://hdl.handle.net/11573/213993 ice wedge isotope composition petrofabric analysis info:eu-repo/semantics/conferenceObject 2009 ftunivromairis 2024-01-17T17:46:46Z From 1998 to 2006, during four summer field seasons, ice wedges were found in 45 sites at depths ranging from 10 to 74 cm beneath the ground surface. The tops of the ice wedges ranged from 5 to 155 cm wide, and their heights varied from 20 to over 150 cm in length. A co-isotopic study was performed by measuring both the oxygen (Delta 18O) and hydrogen (Delta D) isotope compositions and the tritium activity. Petrofabric analyses were also performed on ice-wedge ice to investigate changes in fabric across wedges in relation to the growth mechanism. Data loggers were installed at three ice-wedge polygon sites to monitor the ice-wedge thermal regime. The measurements obtained for Delta 18O and Delta D had extremely negative d- excess values, showing a strong divergence from the snowfalls expected to occur at the elevation of the sites. Sublimation processes were taken into account to define the origin of the ice-wedge ice. The presence of hoarfrost crystals, observed in the ice-wedge cracks during summer field surveys, corroborate that sublimation processes may control the formation of ice in the growth processes of ice wedges. Petrofabric analyses indicated the increasing of crystal size from the ice-wedge centre outward, and in c-axis directions they showed a rotation of crystals from the centre towards the sides. The monitoring of the thermal regime of three ice wedges over a five-year period highlighted that, in winter, extreme gradients between the temperatures at the ground surface and those at the tops of the ice wedges may trigger cracking. Moreover, the presence of open cracks in the ice wedges, in summer, indicates that the growth processes are still active under the present climatic conditions. Conference Object Antarc* Antarctic Sapienza Università di Roma: CINECA IRIS Antarctic |
institution |
Open Polar |
collection |
Sapienza Università di Roma: CINECA IRIS |
op_collection_id |
ftunivromairis |
language |
English |
topic |
ice wedge isotope composition petrofabric analysis |
spellingShingle |
ice wedge isotope composition petrofabric analysis RAFFI, Rossana B. STENNI L. GENONI O. FLORA Geochemical, thermal and petrofabric analyses of Antarctic ice wedges: environmental influences |
topic_facet |
ice wedge isotope composition petrofabric analysis |
description |
From 1998 to 2006, during four summer field seasons, ice wedges were found in 45 sites at depths ranging from 10 to 74 cm beneath the ground surface. The tops of the ice wedges ranged from 5 to 155 cm wide, and their heights varied from 20 to over 150 cm in length. A co-isotopic study was performed by measuring both the oxygen (Delta 18O) and hydrogen (Delta D) isotope compositions and the tritium activity. Petrofabric analyses were also performed on ice-wedge ice to investigate changes in fabric across wedges in relation to the growth mechanism. Data loggers were installed at three ice-wedge polygon sites to monitor the ice-wedge thermal regime. The measurements obtained for Delta 18O and Delta D had extremely negative d- excess values, showing a strong divergence from the snowfalls expected to occur at the elevation of the sites. Sublimation processes were taken into account to define the origin of the ice-wedge ice. The presence of hoarfrost crystals, observed in the ice-wedge cracks during summer field surveys, corroborate that sublimation processes may control the formation of ice in the growth processes of ice wedges. Petrofabric analyses indicated the increasing of crystal size from the ice-wedge centre outward, and in c-axis directions they showed a rotation of crystals from the centre towards the sides. The monitoring of the thermal regime of three ice wedges over a five-year period highlighted that, in winter, extreme gradients between the temperatures at the ground surface and those at the tops of the ice wedges may trigger cracking. Moreover, the presence of open cracks in the ice wedges, in summer, indicates that the growth processes are still active under the present climatic conditions. |
author2 |
Australian and New Zealand Geomorphology Group Raffi, Rossana B., Stenni L., Genoni O., Flora |
format |
Conference Object |
author |
RAFFI, Rossana B. STENNI L. GENONI O. FLORA |
author_facet |
RAFFI, Rossana B. STENNI L. GENONI O. FLORA |
author_sort |
RAFFI, Rossana |
title |
Geochemical, thermal and petrofabric analyses of Antarctic ice wedges: environmental influences |
title_short |
Geochemical, thermal and petrofabric analyses of Antarctic ice wedges: environmental influences |
title_full |
Geochemical, thermal and petrofabric analyses of Antarctic ice wedges: environmental influences |
title_fullStr |
Geochemical, thermal and petrofabric analyses of Antarctic ice wedges: environmental influences |
title_full_unstemmed |
Geochemical, thermal and petrofabric analyses of Antarctic ice wedges: environmental influences |
title_sort |
geochemical, thermal and petrofabric analyses of antarctic ice wedges: environmental influences |
publisher |
Australian and New Zealand Geomorphology Group |
publishDate |
2009 |
url |
http://hdl.handle.net/11573/213993 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
info:eu-repo/semantics/altIdentifier/isbn/9781877040740 ispartofbook:Conference Abstracts 7th International Conference on Geomorphology (ANZIAG). Ancient Landscape-Modern Perspectives firstpage:1 lastpage:1 numberofpages:1 http://hdl.handle.net/11573/213993 |
_version_ |
1790594585871777792 |